WIPvariance

douglas-raillard-arm · Nov 14, 2023 · 77c09f6 · 77c09f6
1 parent 6bb386c
commit 77c09f6
Showing 1 changed file with 10 additions and 4 deletions.
diff --git a/tools/analysis/traceevent/src/buffer.rs b/tools/analysis/traceevent/src/buffer.rs
@@ -131,13 +131,15 @@ impl<'i, 'h, 'edm, InitDescF, T> EventVisitor<'i, 'h, 'edm, InitDescF, T> {
         desc_map: &'edm mut EventDescMap<'h, T, InitDescF>,
     ) -> Self {
 
-        let desc_map: &'edm mut EventDescMap<'h, T, InitDescF> = desc_map;
         // SAFETY: Erase the lifetime 'h and replace by 'static so that we stay covariant in 'h. We
         // won't be using the desc_map reference past 'h since:
         // * 'h outlives 'edm
         // * we don't leak self.desc_map anywhere without attaching the 'edm lifetime to what was
         //   leaked
-        let desc_map: &'edm mut EventDescMap<'static, T, InitDescF> = unsafe {core::mem::transmute(desc_map)};
+        let desc_map: &'edm mut EventDescMap<'static, T, InitDescF> = {
+            let desc_map: &'edm mut EventDescMap<'h, T, InitDescF> = desc_map;
+            unsafe { core::mem::transmute(desc_map) }
+        };
 
         EventVisitor {
             data,
@@ -274,8 +276,12 @@ where
         // borrow it mutably more than once. This makes it safe to turn it back to an &'edm
         // mut.
         let desc_map: *mut *mut EventDescMap<'static, T, InitDescF> = self.desc_map.get();
-        let desc_map: &'edm mut EventDescMap<'static, T, InitDescF> = unsafe { &mut **desc_map };
-        let desc_map: &'edm mut EventDescMap<'h, T, InitDescF> = unsafe{core::mem::transmute(desc_map)};
+        let desc_map: &'edm mut EventDescMap<'static, T, InitDescF> = unsafe {
+            &mut **desc_map
+        };
+        let desc_map: &'edm mut EventDescMap<'h,      T, InitDescF> = unsafe {
+            core::mem::transmute(desc_map)
+        };
         desc_map
     }